Installation:
It works with all three versions of the car. Place the skin folder into any of their respective directories you'd like to.
Standard Version: "assettocorsa\content\cars\ks_abarth_595ss\skins"
S1 Version: "assettocorsa\content\cars\ks_abarth_595ss_s1\skins"
S2 Version: "assettocorsa\content\cars\ks_abarth_595ss_s2\skins".